How to Nearly Eliminate Camera Noise

A fairly common annoyance is your video camera picking up internal noises it makes when you use its built-in microphone. This tutorial will explain one simple method to greatly reduce such noises. While Sonic Foundry does have a stand alone application called Noise Reduction plug-in, it is rather pricey (almost $300) for casual use, which these series of tutorials are targeted at. So I looked for a much cheaper alternative. Of those I tested, Cool Edit 2000 seemed to offer the best price/performance value. I have Audio Cleaning Lab also, however I found it limited in adjusting parameters for this particular task, while it does much better with the other features it offers.

While shooting the short demonstration video that goes with this tutorial (over at Chienworks) I discovered how little things can impact on background noise. Like the furnace starting up, even the refrigerator turning on some twenty five feet away contributed to the background noise that the camera dutifully picked up. So while this tutorial will explain how to make a general noise filter, how successful it works depends on both the size and shape of the room or acoustics, (or outdoor conditions) but also factors like things happening in the background that you take for granted and don't really notice because they are every day happenings which are none the less picked up by your camera's microphone. So for best results you may need to make several noise filters for different situations or better, take the few minutes it takes to make a custom one for each video you edit.

You should finish editing your video before applying any noise reduction. Simply render the audio track that contains background noise you wish to remove as a WAV file, then open in Cool Edit or a similar application. While the illustration only shows the right channel, you want to have both left and right channels selected.

You're looking for a representative area of "silence" between a half a second to no more than a few seconds in length. You may need several dry runs before you find an area on the waveform that works the best. One of the things I like about Cool Edit 2000 it is allows you to vary the strength of the filter though several controls, some shown below.

Low setting (green) cause less distortion, but more of the background noise will remain. More noise reduction is achieved if you use higher settings, (yellow and red) but you will likely clip some of the properties of the waveform you want to keep, and introduce distortions like hollow sounds or robot like speech.

I've found that the sweet spot seems to be somewhere between 45-67 for voice in an otherwise quite room. In the demo video I made, I had a bad cold and I taped it in a room with very high ceilings both of which contributed to less than a ideal result. With a little effort you can probably do better.

Best results seem possible if you change the profile snapshots from the default setting of 1,000 to between 1,500 to 2,000 and set FFT size to 8192.

Click the preview button and if satisfied with the result, name and save the profile. Next select the whole file being sure you have both channels (reopen source file if necessary) then select Noise Reduction from the Transform Menu, load the profile you saved, then click OK and the filter information in the profile will be applied to the whole file. You should see the waveform flatten out considerably if you zoom in in the areas where there is nothing but background noise.

Save as a wav file, open in Vegas Video or Video Factory and carefully align with the original video track, first removing or dropping down the original audio track and muting it. You can further improve results by applying some of SoFo's included FX filters, which vary depending on which package you are editing with.